1. Field of the Invention
The invention relates to a method and apparatus comprising a heat source for making food chips.
2. Brief Description of the Art
Potato food chips and other snack foods are very popular. There are many methods in preparing snack foods such as potato food chips and other forms of vegetable and grain food chips such as corn (maize) or tortilla food chips. Most of these methods rely on cooking the snacks in oil, known as deep frying. The deep frying creates a very crisp structure and lower the moisture content but will allow some uptake of oil. The frying process typical results in a fat content of 20-45% of fat. Fat is very high in calories and heavy intake of calories might lead to overweight. Apart from overweight, high intake of fat may also lead to other health problems such as heart diseases and joint problems, such as knee damages. Most major health organizations thus recommend that no more than thirty percent (30%) of the total calorie intake shall be fat related.
Generally, there are two very important factors when it comes to food; price and taste. It has therefore been an object over a long period of time to cost effectively produce a fat-free snack food product, for instance potato food chips that looks, feels and taste similar to deep fried food chips. Having recognized the long felt need, other inventors have attempted to produce commercially acceptable fat-free potato food chips. Earlier attempts have required considerable economic investments in microwave or radio wave techniques or have not got the desirable taste and structure similar to deep fried food chips.
In a process disclosed in U.S. Pat. No. 4,283,425, a single step of heating by microwaves (910-915 mhz or 2400-2500 mhz) was used. The slices were also dipped in or sprayed with an edible oil prior to final microwave cooking, which led to a fat content of 3-5% by weight, which as such is too high to be classified as fat-free. Thus, this product was basically a “low-fat” potato food chip.
In a further process disclosed in U.S. Pat. No. 4,800,090, sliced potatoes were first subjected to an infrared (high intensity 46 micron wavelength) heating step to heat their exterior, then to a microwave energy (915-2450 mhz) heating step to heat their interior, and finally to another infrared (4-6 micron wavelength) heating step to brown them into a crisp, fat-free, potato food chip snack food product that was low in calories and had a long shelf life.
U.S. Pat. No. 4,906,483 discloses a process in which the microwave cooking step was employed early in the process to activate the release of starch while the potato slices were still immersed in water followed by a cold water rinse and final cooking in radiant heat until brown and crisp to produce a fat-free potato food chip.
U.S. Pat. No. 5,470,600 discloses a process in which the slices are initially cooked in a three zone primary oven by first radiant heating the slices and then subjecting the slices to two successive stages of forced air heating and a final cooking in a dielectric heater by subjecting the slices to radio frequency electromagnetic waves having a long wavelength.
A still further fat-free process is disclosed in U.S. Pat. No. 4,919,965, in which the potato slices are simultaneously finally cooked by compressing them between dual opposed heating surfaces which were 50% relieved driving the moisture into the voids in the cooking surfaces to produce a fat-free potato food chip.